U.S. patent application number 12/693266 was filed with the patent office on 2010-05-20 for inspection apparatus and method.
This patent application is currently assigned to Hitachi High-Technologies Corporation. Invention is credited to Masaaki Komori, Kouichi Kurosawa, Takeshi Sato, Takeshi Sunaoshi.
Application Number | 20100123474 12/693266 |
Document ID | / |
Family ID | 40220937 |
Filed Date | 2010-05-20 |
United States Patent
Application |
20100123474 |
Kind Code |
A1 |
Sunaoshi; Takeshi ; et
al. |
May 20, 2010 |
INSPECTION APPARATUS AND METHOD
Abstract
There are provided an inspection apparatus and method that can
locally perform sample temperature regulation, so that the sample
drift can be suppressed. There are included a sample stage 109 that
holds a semiconductor sample 118, multiple probes 106 used to
measure electrical characteristics of a semiconductor device on the
semiconductor sample 118, a power source that applies voltage
and/or current to the probe 106, a detector that measures
electrical characteristics of the semiconductor device on the
sample with which the probe is brought into contact, and an
electromagnetic wave irradiating mechanism that irradiates
electromagnetic wave on a measurement section of the semiconductor
sample 118.
Inventors: |
Sunaoshi; Takeshi;
(Hitachinaka, JP) ; Kurosawa; Kouichi; (Hitachi,
JP) ; Sato; Takeshi; (Hitachinaka, JP) ;
Komori; Masaaki; (Hitachinaka, JP) |
Correspondence
Address: |
MCDERMOTT WILL & EMERY LLP
600 13TH STREET, N.W.
WASHINGTON
DC
20005-3096
US
|
Assignee: |
Hitachi High-Technologies
Corporation
Tokyo
JP
|
Family ID: |
40220937 |
Appl. No.: |
12/693266 |
Filed: |
January 25, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
12146029 |
Jun 25, 2008 |
7663390 |
|
|
12693266 |
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Current U.S.
Class: |
324/754.29 ;
324/501; 324/756.02 |
Current CPC
Class: |
G01R 31/311 20130101;
G01R 31/2874 20130101 |
Class at
Publication: |
324/754 ;
324/501 |
International
Class: |
G01R 31/02 20060101
G01R031/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 25, 2007 |
JP |
2007-165899 |
Claims
1. An inspection apparatus comprising: a sample stage that holds a
sample; a plurality of probes used to measure electrical
characteristics of a semiconductor device on the sample; a drive
unit that faces the sample and drives the probe; a power source
that applies voltage and/or current to the probe; a detector that
measures electrical characteristics of the semiconductor device on
the sample with which the probe is brought into contact; and an
electromagnetic wave irradiating mechanism that irradiates
electromagnetic wave on the sample.
2-12. (canceled)
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to an inspection apparatus and
method that inspects electrical characteristics of a semiconductor
device by use of a probe.
[0003] 2. Background Art
[0004] As an inspection apparatus used to inspect electrical
defects of a microscopic electrical circuit formed on a
semiconductor chip, there are known inspection apparatuses
including: an electrical beam tester that irradiates an electrical
beam and detects electrically defective sections of an LSI, using
the fact that the discharge rate of secondary electron from a
measurement point varies according to the voltage value at the
measurement section; and a probe apparatus in which multiple
mechanical probes (exploring needles) arranged in a manner adjusted
to the position of a characteristic measuring pad formed on an LSI
is brought into contact with the measuring pad, so that electrical
characteristics of the LSI are measured. Examples of the techniques
related to such probe apparatus include ones described in Patent
Documents 1, 2 and 3.
[0005] Patent Document 1 describes a defect inspection apparatus in
which a probe (exploring needle) is arranged in a sample chamber of
SEM (Scanning Electron Microscope), and the tip end of the probe is
brought into contact with a desired section of an electrical device
being the test sample while the electrical device is observed using
the SEM, so that electrical characteristics of the microscopic
electrical device are measured.
[0006] Patent Document 2 describes a defect inspection apparatus
using a scanning electron microscope, the apparatus including:
separate drive apparatuses which respectively drive a probe and a
sample table on which a sample is placed; and a base stage drive
apparatus which drives the probe and sample table in an integrated
manner, wherein there is used a CAD navigation system which uses
data of scanning electron microscope images and wire layout, so
that scanning electron microscope images at a desired contact
section are acquired to perform probe contact.
[0007] Patent Document 3 describes a defect inspection apparatus
including GUI (Graphical User Interface) used to easily control the
position, operation and the like of multiple probes which can be
driven separately.
[0008] [Patent Document 1] JP Patent Publication (Kokai) No.
9-326425A
[0009] [Patent Document 2] JP Patent Publication (Kokai) No.
2005-210067A
[0010] [Patent Document 3] JP Patent Publication (Kokai) No.
2006-125909A
SUMMARY OF THE INVENTION
[0011] In recent years, in the fields of semiconductor device
electrical characteristic evaluation techniques, there is
increasing demand for temperature characteristic evaluation
techniques for reliability and safety evaluation of semiconductor
device, in addition to electrical characteristic evaluation of the
electrical circuit and electrical characteristic evaluation of the
constituent semiconductor.
[0012] In a temperature characteristic evaluation according to
related art, a semiconductor sample to be inspected is secured to a
sample table; and the following operation is repeated. That is,
first, at room temperature, the tip end of a probe is brought into
contact with a measurement pad of the semiconductor sample to
measure electrical characteristics, and thereafter the tip end is
slightly withdrawn, and subsequently the temperature of the whole
sample is regulated (heating or cooling), and after the sample has
reached thermal balance, the probe tip end is brought into contact
with the measurement pad of the semiconductor sample to measure
electrical characteristics, and thereafter the tip end is slightly
withdrawn.
[0013] In such temperature characteristic evaluation, during the
temperature regulation, the temperature of the whole sample chamber
containing the sample table, probing mechanism and the like is
varied, and thus expansion and contraction of the sample table,
probing mechanism and the like caused by this temperature variation
produces sample drift. Accordingly, the probe contact position must
be adjusted each time the temperature regulation is performed, so
it takes much labor; and at the same time, the length of time taken
from when temperature regulation is performed to when thermal
balance is reached so that the sample drift stops, is very long,
causing throughput deterioration. In order to improve the
throughput, the probe may be brought into contact with the
measurement pad during the sample drift to measure electrical
characteristics. However, such forced contact operation during the
sample drift causes breakage or wear of the probe tip end and the
sample measurement pad, resulting in life shortening of the probe
and test sample. Further, the increase in electrical noise caused
by heating of the sample table, probing mechanism and the like may
have adverse influence on measurement accuracy and measurement
stability.
[0014] To address the above problem, the present invention has been
devised, and its object is to provide an inspection apparatus and
method that can locally perform sample temperature regulation, so
that the sample drift can be suppressed.
[0015] To achieve the above object, the present invention includes:
a sample stage that holds a sample; and an electromagnetic wave
irradiating apparatus that irradiates electromagnetic wave on the
sample, wherein the temperature of the sample is regulated by
irradiating electromagnetic wave on the sample.
[0016] According to the present invention, since electromagnetic
wave is irradiated on a measurement section of the sample to
perform sample temperature regulation, sample temperature
regulation can be locally performed, so that sample drift can be
suppressed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a view illustrating an overall configuration of a
defect inspection apparatus according to a first embodiment of the
present invention.
[0018] FIG. 2 is a lateral view of an optical microscope image when
an electrical characteristic measurement according to the first
embodiment of the present invention is performed.
[0019] FIG. 3 is a view illustrating an SEM image when an
electrical characteristic measurement according to the first
embodiment of the present invention is performed.
[0020] FIG. 4 is a view illustrating details of an optical fiber
according to a second embodiment of the present invention.
[0021] FIG. 5 is a view illustrating an SEM image according to the
second embodiment of the present invention.
[0022] FIG. 6 is a view illustrating an overall configuration of a
defect inspection apparatus according to a third embodiment of the
present invention.
[0023] FIG. 7 is a view illustrating an example of attachment and
its connection according to the third embodiment of the present
invention.
[0024] FIG. 8 is a view illustrating details of the attachment
according to the third embodiment of the present invention.
[0025] FIG. 9 is a view illustrating details of the tip end
according to the third embodiment of the present invention.
[0026] FIG. 10 is a lateral view of an optical microscope image
when an electrical characteristic measurement according to the
third embodiment of the present invention is performed.
[0027] FIG. 11 is a view illustrating an SEM image when the
electrical characteristic measurement according to the third
embodiment of the present invention is performed.
[0028] FIG. 12 is a view illustrating an attachment and its
connection according to the third embodiment of the present
invention.
DESCRIPTION OF SYMBOLS
[0029] 1 SEM [0030] 2 SAMPLE DRIVE APPARATUS [0031] 3, 3A SAMPLE
MEASURING APPARATUS [0032] 4 CONTROL SYSTEM [0033] 5, 5A
ELECTROMAGNETIC WAVE CONTROL SYSTEM [0034] 100, 100A DEFECT
INSPECTION APPARATUS [0035] 101 ELECTRICAL BEAM COLUMN [0036] 102
VACUUM CHAMBER CONFINING WALL [0037] 103 PRIMARY ELECTRON BEAM
[0038] 104 SECONDARY ELECTRON DETECTOR [0039] 105 SECONDARY
ELECTRON [0040] 106 PROBE (MECHANICAL PROBE) [0041] 107, 107A, 107B
ATTACHMENT [0042] 108 PROBE DRIVE UNIT [0043] 109 SAMPLE TABLE
[0044] 110 SAMPLE TABLE DRIVE APPARATUS [0045] 111 BASE STAGE
[0046] 112 BASE [0047] 113 ELECTRICAL CHARACTERISTIC MEASURING UNIT
[0048] 114 CONTROL COMPUTER [0049] 115 STORAGE DEVICE [0050] 116
ELECTRON GUN CONTROL APPARATUS [0051] 117 SEM CONTROL PC [0052] 118
SEMICONDUCTOR SAMPLE [0053] 119, 120 OPTICAL FIBER [0054] 121
ELECTROMAGNETIC WAVE SOURCE [0055] 122 ELECTROMAGNETIC WAVE
MEASURING MECHANISM [0056] 123 ELECTROMAGNETIC WAVE CONTROL
MECHANISM [0057] 124 ELECTROMAGNETIC WAVE SOURCE AND
ELECTROMAGNETIC WAVE MEASURING MECHANISM [0058] 125A, 125B TIP END
[0059] 126, 126A, 126B, 127 OPTICAL FIBER [0060] 203 TO 206
MEASUREMENT PAD [0061] 227 OPTICAL FIBER [0062] 301 OPTICAL FIBER
UNIT [0063] 302 LENS UNIT [0064] 303 OPTICAL FIBER [0065] 304
PROCESSING MARKING
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0066] Embodiments of the present invention will be described with
reference to the drawings.
[0067] A first embodiment of the present invention will be
described with reference to FIGS. 1 to 4.
[0068] FIG. 1 is a view illustrating an overall configuration of a
defect inspection apparatus according to the present
embodiment.
[0069] Referring to FIG. 1, a defect inspection apparatus 100
according to the present embodiment includes an SEM (Scanning
Electron Microscope: hereinafter referred to as an SEM) 1, sample
drive apparatus 2, sample measuring apparatus 3, control system 4,
electromagnetic wave control system 5 and SEM control PC 117.
[0070] The SEM 1 includes an electron source (not illustrated) that
emits primary electron beam 103, an electron beam optical system
that guides the primary electron beam 103 and irradiates it on a
semiconductor sample 118 being the test sample, secondary electron
detector 104 that detects secondary electron 105 emitted from the
semiconductor sample 118 by irradiation of the primary electron
beam 103, and electron beam optical system control apparatus 116
that controls the operation of the electron beam optical system,
i.e., the electron beam withdrawing voltage of the electron source
and the applied voltage to a deflector lens. The electron beam
optical system according to the present embodiment constitutes an
irradiation optical system that irradiates the primary electron
beam 103 on the test sample and at the same time, scans the test
sample, and includes an electron source that generates electron
beam, a deflection apparatus used for beam scanning, and a lens
used to focus electron beam.
[0071] The defect inspection apparatus 100 according to the present
embodiment further includes multiple optical microscopes, CCD
cameras (not illustrated) and the like used to acquire top or side
images of the semiconductor sample 118 held on a sample table 109
arranged inside a vacuum chamber confining wall 102.
[0072] The vacuum chamber confining wall 102 is a wall which
separates the atmospheric pressure area and vacuum area. An
irradiation unit of an electron beam column 101 which covers the
electron beam optical system of the SEM 1, and a sensor unit of the
secondary electron detector 104 which detects electron are arranged
inside the vacuum chamber confining wall 102; but the units to
which power and transmission lines are connected, protrude to the
outside of the vacuum chamber confining wall 102. That is, the
electron beam column 101 which covers the electron beam optical
system of the SEM 1, and the secondary electron detector 104 are
arranged so as to penetrate through the vacuum chamber confining
wall 102.
[0073] The sample drive apparatus 2 includes: the sample table 109
which holds the semiconductor sample 118; a sample table drive
apparatus 110 which holds the sample table 109 and drives the
sample table 109 in an X and Y (horizontal) direction; a base stage
111 which holds the sample table drive apparatus 110 and includes a
drive apparatus which drives the sample table drive apparatus 110
in an X, Y (horizontal) and Z (vertical) direction; and a base 112
which holds the base stage 111. The sample table 109 and sample
table drive apparatus 110 are collectively referred to as a sample
stage. On the base stage 111, there is held a probe drive unit (to
be described later) 108 along with the sample stage; and when the
base stage 111 is driven and moved relative to the base 112, the
sample stage and probe drive unit 108 can be driven in an
integrated manner. The sample stage, base stage 111 and base 112
are arranged inside the vacuum chamber confining wall 102.
[0074] The sample measuring apparatus 3 includes: multiple (for
example, 6) mechanical probes (only two of them illustrated in FIG.
1) 106 which are brought into contact with a given section of the
semiconductor sample 118; multiple (for example, 6) attachments 107
being probe holders which hold each of the multiple mechanical
probes (hereinafter, simply referred to as a probe) 106; multiple
(for example, 6) probe drive units 108 which hold each of the
attachments 107 and moves the probe 106 to a desired position along
with the attachment 107; and an electrical characteristic measuring
unit 113 which measures electrical characteristics of the
semiconductor sample 118 through the probe 106.
[0075] The probe 106 is brought into contact with predetermined
sections such as measurement pads 203, 204, 205 and 206 (refer to
FIG. 3 to be described later) of the semiconductor sample 118;
electrical characteristics of the semiconductor sample 118 are
measured through the probe 106 (the measurement will be described
later).
[0076] The probe drive unit 108 is held on the base stage 111 along
with the sample stage of the sample drive apparatus 2. The six
probe drive units 108 drive the respective probes 106 in an X, Y
(horizontal) and Z (vertical) direction on a per attachment 107
basis.
[0077] In the sample stage, the semiconductor sample 118 can be
driven by driving the sample table 109; and the probe drive units
108 can drive the six probes 106 separately; and the base stage 111
can drive the sample stage and probe drive unit 108 in an
integrated manner. Accordingly, the semiconductor sample 118 and
probe 106 can be driven separately or in an integrated manner.
Further, when the sample table 109 is driven and moved by the
sample table drive apparatus 110 relative to the base stage 111,
the relative position between the six probes 106 and the
semiconductor sample 118 can be varied without varying the relative
position between the six probes 106.
[0078] The electrical characteristic measuring unit 113 of the
sample measuring apparatus 3 is installed outside the vacuum
chamber confining wall 102; and the probes 106, attachments 107 and
probe drive units 108 are installed inside the vacuum chamber
confining wall 102.
[0079] The electrical characteristic measuring unit 113 includes: a
power source (not illustrated) which applies through the probes
106, current and voltage to desired sections of the semiconductor
sample 118 such as the measurement pads 203, 204, 205 and 206
(refer to FIG. 3 to be described later); and a detector (not
illustrated) which detects current and voltage at the desired
sections of the semiconductor sample 118. The sample table 109 and
attachments 107 are connected to the electrical characteristic
measuring unit 113; and the electrical characteristic measuring
unit 113 measures current-voltage characteristics of the
semiconductor sample 118 mainly through the probes 106 and
attachments 107, and calculates desired characteristic values based
on the current-voltage characteristics. Examples of the
characteristic values include a current value, voltage value and
resistance value at a section with which the probe 106 is brought
into contact. As with the present embodiment, when a semiconductor
sample is used as the test sample, a semiconductor parameter
analyzer is used as the electrical characteristic measuring unit
113, for example. Waveforms and characteristic values (hereinafter,
simply referred to as electrical characteristic data) of the
current-voltage characteristics of the semiconductor sample 118
measured by the electrical characteristic measuring unit 113 are
sent to a control computer 114 of the control system 4 via a
transmission line.
[0080] The electromagnetic wave control system 5 includes; an
electromagnetic wave source (electromagnetic wave generating
apparatus) 121 which generates electromagnetic wave; an optical
fiber 120 used to irradiate the electromagnetic wave generated by
the electromagnetic wave source 121 on a measurement section of the
semiconductor sample 118; an electromagnetic wave measuring
mechanism 122 which detects an intensity of electromagnetic wave
emitted from the measurement section of the semiconductor sample
118; an optical fiber 119 used to transmit electromagnetic wave
radiated from the measurement section of the semiconductor sample
118 to the electromagnetic wave measuring mechanism 122; and an
electromagnetic wave control mechanism 123 which calculates a
temperature of the semiconductor sample 118 based on the intensity
of the electromagnetic wave (for example, infrared) measured by the
electromagnetic wave measuring mechanism 122 and outputs the
temperature data to the control computer 114 and at the same time,
regulates the frequency and intensity of electromagnetic wave
generated by the electromagnetic wave source 121 based on a command
signal from the control computer 114. In the present example, the
electromagnetic wave measuring mechanism 122 and electromagnetic
wave control mechanism 123 constitutes a temperature measuring
mechanism which measures a temperature at an electromagnetic wave
irradiation section of the semiconductor sample 118. Here, when the
electromagnetic wave measuring mechanism 122 has a function to
convert an electromagnetic wave detection value to a temperature
measurement value, the electromagnetic wave measuring mechanism 122
can perform temperature measurement alone; thus the function to
calculate a temperature of the semiconductor sample 118 can be
omitted in the electromagnetic wave control mechanism 123.
[0081] The electromagnetic wave source 121 can generate
electromagnetic wave of different frequencies. Examples of specific
methods for regulating the frequency of generated electromagnetic
wave include one which selects the type of light source which
generates electromagnetic wave, and one which selects and outputs
electromagnetic wave of a given frequency from among
electromagnetic waves from an electromagnetic wave generating light
source. An example of the former method is one which rotates a
light source switching mechanism in which light sources generating
electromagnetic wave of a different frequency are arranged in a
revolver-like shape, whereby the type of light source is varied. An
example of the latter method is one which selects a given
wavelength using a diffraction grating. The electromagnetic wave
source 121 generates electromagnetic wave such as infrared ray
(wavelength: 0.7 .mu.m to 1 mm) and ultraviolet ray (wavelength: 10
nm to 400 nm).
[0082] The electromagnetic wave source 121, electromagnetic wave
measuring mechanism 122 and electromagnetic wave control mechanism
123 are installed in the outside of the vacuum chamber confining
wall 102. The optical fibers 119 and 120 having one end thereof
connected to the electromagnetic wave source 121 and
electromagnetic wave measuring mechanism 122 are arranged so as to
penetrate through the vacuum chamber confining wall 102; the other
end thereof is arranged in the vicinity of a measurement section of
the semiconductor sample 118, the tip end thereof facing the
measurement section (refer to FIG. 2 to be described later).
[0083] The control system 4 includes the control computer 114 and a
storage device 115 such as memory. The electrical characteristic
data of the semiconductor sample 118 measured by the electrical
characteristic measuring unit 113 and sent to the control computer
114 are stored in the storage device 115 included in the control
computer 114, such as an optical disk, hard disk or memory; and the
control computer 114 analyzes the electrical characteristics and
thereby determines whether or not there is a defect at the
measurement section of the semiconductor sample 118. Further, the
control computer 114 also plays a role of controlling the operation
of the whole defect inspection apparatus 100; after parameters for
each apparatus have been set through an input unit, the control
computer 114 controls, according to software stored in the storage
device 115, the constituent apparatuses including an electron gun
control apparatus 116, secondary electron detector 104,
electromagnetic wave control mechanism 123, sample stage and base
stage 111.
[0084] An SEM control PC 117 controls, according to a GUI
(Graphical User Interface) operation or a command input to the
keyboard, the optical conditions, magnifying power, focusing, image
shift, SEM image brightness, scan speed, alignment, image recording
of the SEM 1, and the position of the sample stage of the sample
drive apparatus 2, and the position of the probe 106 of the sample
measuring apparatus 3. The SEM control PC 117 sends a control
signal via the control computer 114 to the electron gun control
apparatus 116 to thereby control the electron beam optical system
(not illustrated), and acquire a detection signal detected by the
secondary electron detector 104, and controls the operations of the
sample table drive apparatus 110, base stage 111, probe drive unit
108, optical microscope, CCD camera and the like.
[0085] FIG. 2 is a lateral view of an optical microscope image when
an electrical characteristic measurement is performed at a defect
inspection apparatus according to the present embodiment of the
present invention.
[0086] Referring to FIG. 2, the semiconductor sample 118 is held on
the sample table 109; and on a measurement section of the
semiconductor sample 118, there is irradiated the primary electron
beam 103 from the electron beam optical system (not illustrated) of
the SEM 1 and at the same time, the probe 106 is brought into
contact with the measurement pads (refer to FIG. 3 to be described
later) 203, 204, 205 and 206. Further, one ends of the optical
fibers 119 and 120 are arranged in the vicinity of the measurement
section of the semiconductor sample 118, the tips ends thereof
facing the measurement section. In this state, electromagnetic wave
(for example, infrared or ultraviolet) is generated by the
electromagnetic wave source 121 and irradiated via the optical
fiber 120 to the measurement section of the semiconductor sample
118.
[0087] For example, when infrared (for example, far-infrared ray of
wavelength 4 .mu.m to 1 mm) is generated by the electromagnetic
wave source 121 and irradiated via the optical fiber 120 to the
measurement section of the semiconductor sample 118, the
measurement section is locally heated by the working of irradiated
infrared. All sorts of materials emit infrared of an intensity
proportional to its temperature; the infrared emitted from the
measurement section is inputted via the optical fiber 119 to the
electromagnetic wave measuring mechanism 122 to measure the
infrared, and data of the infrared intensity is sent to the
electromagnetic wave control mechanism 123, whereby the temperature
of the measurement section of the semiconductor sample 118 can be
measured based on the data. The control computer 114 regulates the
intensity of infrared generated by the electromagnetic wave source
121 so that the difference between a setting temperature and the
temperature of the measurement section of the semiconductor sample
118 thus acquired is reduced, whereby the temperature of the
measurement section is regulated.
[0088] When ultraviolet ray (wavelength: 10 nm to 400 nm) is
generated by the electromagnetic wave source 121 and irradiated via
the optical fiber 120 on the measurement section of the
semiconductor sample 118, charging and contamination on the surface
of the semiconductor sample 118 can be removed. As the
electromagnetic wave effective in eliminating charging, there is
known ultraviolet ray of wavelength of 253.7 nm, for example. Also,
for example, while a proper amount of oxygen is brought into the
vacuum chamber confining wall 102, when ultraviolet rays of
wavelengths of, for example, 184.9 nm and 257.7 nm (generated by a
low-pressure ultraviolet lamp or the like) are irradiated on the
semiconductor sample 118, contaminants (for example, organic matter
such as carbon and the like) on the surface of the semiconductor
sample 118 can be removed.
[0089] FIG. 3 is a view illustrating an SEM image when electrical
characteristics of the semiconductor sample 118 is measured.
[0090] Referring to FIG. 3, the semiconductor sample 118 includes
measurement pads 203, 204, 205 and 206 connected respectively to
the source, drain, gate and well, and four probes 106 of the six
probes 106 included in the sample measuring apparatus 3 are brought
into contact with the respective measurement pads by the probe
drive unit 108 and the like. Two probes 106 not brought into
contact with the measurement pads are withdrawn to a position which
does not interrupt the driving of the other probes 106 and the
like.
[0091] In this state, voltage is applied via the measurement probe
106 to a desired measurement pad by the electrical characteristic
measuring unit 113, and voltage and current of the desired
measurement pad are measured via the measurement probe 106, whereby
electrical characteristic data of the semiconductor sample 118 are
acquired. For example, while voltage is applied between the
measurement pad 203 connecting to the source and the measurement
pad 204 connecting to the drain, when voltage is applied to the
measurement pad connecting to the gate to measure current flowing
between the measurement pad (source) 203 and the measurement pad
(drain) 204, waveform (current-voltage characteristics) indicating
a relationship between the gate voltage and drain current at the
given source-drain voltage can be acquired. The waveform of
current-voltage characteristics and the electrical characteristic
data such as the characteristic values are displayed on a display
unit (not illustrated) of the electrical characteristic measuring
unit 113 and at the same time, sent to the control computer
114.
[0092] The operation of the present embodiment having the above
configuration will be described.
[0093] In the defect inspection apparatus 100 according to the
present embodiment, when a semiconductor sample 118 being an
exemplary test sample is measured, the semiconductor sample 118 is
held on the sample table 109.
[0094] First, while the SEM control PC 117 is manipulated and the
positional relationship in a horizontal and vertical direction
between the measurement section of the semiconductor sample 118 and
the four probes 106 used in the present embodiment is observed
based on low-magnification observation images of the optical
microscope, the four probes 106 are driven in a horizontal and
vertical direction, whereby the proportional positional
relationship between the measurement section of the semiconductor
sample 118 and the four probes 106 is made to approach a range
which can be observed by the SEM 1.
[0095] Subsequently, while the measurement section of the
semiconductor sample 118 and the four probes 106 are observed using
the SEM 1, for example, the four probes 106 are brought into
contact with desired measurement pads of the semiconductor sample
118.
[0096] In this state, electric power is supplied by the electrical
characteristic measuring unit 113 such as a semiconductor parameter
analyzer, so that voltage and current are supplied via the desired
probes 106 to the measurement pads of the semiconductor sample 118;
at the same time, voltage and current of the measurement pads of
the semiconductor sample 118 are measured through the desired
probes 106, whereby waveforms of current-voltage characteristics of
the semiconductor sample 118 at room temperature are acquired. The
electrical characteristic measuring unit 113 calculates based on
current-voltage characteristics, the desired characteristic values
such as current value, voltage value and resistance value, and
displays the characteristic values and the waveforms of
current-voltage characteristics on a display unit (not illustrated)
and at the same time, sends them via a transmission line to the
control computer 114. The control computer 114 stores the
characteristic values sent from the electrical characteristic
measuring unit 113 into the storage device 115 and at the same
time, analyzes the characteristic values and thereby determines
whether or not there is a defect at the measurement section of the
semiconductor sample 118. After the measurement of current-voltage
characteristics of the semiconductor sample 118 at room
temperature, the supplying of current and voltage to the
measurement pads of the semiconductor sample 118 is terminated.
[0097] Subsequently, the measurement section temperature of the
semiconductor sample 118 is set using the input unit of the control
computer 114. The control computer 114 controls the electromagnetic
wave control mechanism 123 to cause the electromagnetic wave source
121 to generate infrared ray (for example, far-infrared ray of
wavelength of 4 .mu.m to 1 mm), and the infrared ray is irradiated
via the optical fiber 120 on the measurement section of the
semiconductor sample 118, whereby the measurement section is
locally heated. Here, before being brought into contact with the
sample, the probe 106 is moved into the electromagnetic wave
irradiation area, so that the probe 106 is also heated and thus the
thermal loss and thermal expansion occurring when the probe is in
contact with the sample can be prevented from occurring. Here, in a
state where the probe is brought into contact at room temperature,
the probe and the measurement section of the sample may be
irradiated with electromagnetic wave while in the contact state.
When the temperature of the measurement section of the
semiconductor sample 118 reaches a desired setting temperature and
stabilizes, the electrical characteristic measuring unit 113
applies via a desired probe 106, voltage and current to the
measurement pad of the semiconductor sample 118 and at the same
time, measures via a desired probe 106 voltage and current of the
measurement pad of the semiconductor sample 118, whereby waveforms
of current-voltage characteristics of the semiconductor sample 118
at the desired high temperature can be acquired. The electrical
characteristic measuring unit 113 calculates characteristic values
based on the current-voltage characteristics, displays the
characteristic values and the current-voltage characteristics on a
display unit and at the same time, sends them via the transmission
line to the control computer 114. The control computer 114 stores
the characteristic values sent from the electrical characteristic
measuring unit 113 into the storage device 115 and at the same
time, analyses the characteristic values and thereby determines
whether or not there is a defect at the measurement section of the
semiconductor sample 118.
[0098] In this way, since the measurement section of the
semiconductor sample 118 is locally heated, sample drift caused by
thermal expansion of the sample drive apparatus 2 and sample
measuring apparatus 3 is suppressed differently from when the whole
sample is heated. Consequently, when the change of temperature is
made while the probe 106 is in contact with the measurement pad,
the bending force exerted on the probe 106 by sample drift can be
suppressed. Accordingly, even when the change of temperature is
made while the probe 106 is in contact with the measurement pad,
the load exerted on the probe 106 and measurement pad can be
suppressed.
[0099] According to the present embodiment having the above
configuration, since the measurement section of the semiconductor
sample 118 is locally heated, the expansion and contraction of the
sample drive apparatus 2 and sample measuring apparatus 3 can be
suppressed and thus the change of temperature can be made while the
sample drift is suppressed. Accordingly, when the change of
temperature of the semiconductor sample 118 is made, the
measurement does not need to be interrupted, as with the related
art, until the sample drift settles; thus the throughput can be
improved significantly, compared to the related art by which there
is a wait until the sample drift settles.
[0100] Further, it is possible to prevent the increase in
electrical noise caused by heating of the sample drive apparatus,
sample measuring apparatus and the like, so measurement accuracy
and measurement stability can be ensured.
[0101] Further, it is possible to heat a desired section of the
semiconductor sample 118 to a desired temperature, so adsorbate
such as carbon attached to the desired section of the semiconductor
sample 118 can be removed when heated.
[0102] Further, ultraviolet ray is irradiated on a desired section
of the semiconductor sample 118, so charging and sample
contamination of the desired section can be removed at the time of
observation by the SEM 1, thus allowing prolonged and stable
observation.
[0103] A second embodiment of the present invention will be
described with reference to FIGS. 4 and 5. The present embodiment
includes a lens used to focus the irradiation range of
electromagnetic wave, the lens being disposed at the tip end of the
optical fiber for electromagnetic wave irradiation according to the
first embodiment.
[0104] FIG. 4 is a view illustrating the tip end of the optical
fiber for electromagnetic wave irradiation according to the present
embodiment.
[0105] Referring to FIG. 4, an optical fiber 303 for
electromagnetic wave irradiation according to the present
embodiment includes an optical fiber unit 301 that transmits
electromagnetic wave generated by the electromagnetic wave source
121, and a lens unit 302 that focuses the transmitted
electromagnetic wave. The electromagnetic wave (for example,
far-infrared ray of wavelength 4 .mu.m to 1 mm) generated by the
electromagnetic wave source 121 is transmitted via the optical
fiber unit 301, focused by the lens unit 302 and then irradiated,
so a processing marking can be made on the semiconductor sample
118.
[0106] FIG. 5 is a view illustrating an example of SEM image
according to the present embodiment. In the SEM image illustrated
in FIG. 5, there are illustrated a semiconductor sample 118, four
probes 106 and optical fiber 303. When the sample table 109 is
driven, along with the semiconductor sample 118, in an X and Y
(horizontal) direction by the sample table drive apparatus 110
while infrared ray generated by the electromagnetic wave source 121
is irradiated via the optical fiber 303 on the semiconductor sample
118, a square-shaped processing marking can be made as indicated by
reference numeral 304 in FIG. 5.
[0107] The other constituent components are identical to those of
the first embodiment of the present invention.
[0108] According to the present embodiment having the above
configuration, the electromagnetic wave generated by the
electromagnetic wave source 121 can be focused and irradiated on a
desired section of the semiconductor sample 118, so a processing
marking can be made at the irradiation position.
[0109] Further, when the semiconductor sample 118 is driven along
with the sample table 109 while infrared ray is irradiated on the
semiconductor sample 118, a processing marking having a given shape
can be made on the semiconductor sample 118.
[0110] In the present embodiment, there was described a case where
the square-shaped processing marking 304 is made, but the present
invention is not limited thereto; when the semiconductor sample 118
is driven in a given direction (horizontal direction), a processing
marking having a given shape can be made.
[0111] A third embodiment of the present invention will be
described with reference to FIGS. 6 to 11. In the drawings, the
same reference numerals are applied to parts corresponding to those
of FIG. 1, and an explanation thereof is omitted. According to the
present embodiment, part of the probe attachment can be replaced
with an attachment of the optical fiber for electromagnetic wave
irradiation, and the optical fiber for electromagnetic wave
irradiation can be driven.
[0112] FIG. 6 is a view illustrating an overall configuration of a
defect inspection apparatus 100A according to the present
embodiment.
[0113] Referring to FIG. 6, the defect inspection apparatus 100A
according to the present embodiment includes an SEM (Scanning
Electron Microscope: hereinafter, referred to as an SEM) 1, sample
drive apparatus 2, sample measuring apparatus 3A, control system 4,
electromagnetic wave control system 5A and SEM control PC 117.
[0114] The sample measuring apparatus 3A includes: multiple (for
example, 4) probes (only one of them illustrated in FIG. 6) 106
which are brought into contact with a given section of the
semiconductor sample 118; an optical fiber 127 used to irradiate
electromagnetic wave on a desired section of the semiconductor
sample 118; an optical fiber 227 (refer to FIG. 10 to be described
later) used to receive electromagnetic wave radiated from the
desired section of the semiconductor sample 118; multiple (for
example, 6) attachments 107a which hold the probes 106 and the
optical fibers 127 and 227 through tip ends 125a and 125b,
respectively; multiple (for example, 6) probe drive units 108 which
hold each of the attachments 107a and moves each of the probe 106
and optical fibers 127 and 227 to a desired position along with the
attachment 107a; and an electrical characteristic measuring unit
113 which measures electrical characteristics of the semiconductor
sample 118 through the probe 106.
[0115] The tip ends 125a and 125b held by the attachment 107a are
detachable, and can be replaced with various types of tip ends
which hold the probe 106 and optical fibers 127 and 227.
[0116] The electromagnetic wave control system 5A includes: an
electromagnetic wave source and electromagnetic wave measuring
mechanism 124 which generates and outputs electromagnetic wave and
at the same time, measures the intensity of received
electromagnetic wave; an optical fiber 126 used to transmit the
electromagnetic wave generated by the electromagnetic wave source
and electromagnetic wave measuring mechanism 124 to the optical
fiber 127; an optical fiber (not illustrated) used to transmit the
electromagnetic wave received by the optical fiber 227 to the
electromagnetic wave source and electromagnetic wave measuring
mechanism 124; and an electromagnetic wave control mechanism 123
which calculates a temperature of the semiconductor sample 118
based on the intensity of electromagnetic wave measured by the
electromagnetic wave source and electromagnetic wave measuring
mechanism 124 and outputs the temperature data to the control
computer 114 and at the same time, regulates based on a command
signal from the control computer 114, the frequency and intensity
of electromagnetic wave generated by the electromagnetic wave
source and electromagnetic wave measuring mechanism 124.
[0117] The electromagnetic wave source and electromagnetic wave
measuring mechanism 124 can vary the frequency of generated
electromagnetic wave; the electromagnetic wave is generated, for
example, using a method of changing or selecting, in a manner of
revolver, a light source generating electromagnetic wave of a
different frequency, or a method of selecting each wavelength by
use of diffraction grating. The electromagnetic wave source 121
generates electromagnetic wave such as infrared ray (wavelength:
0.7 .mu.m to 1 mm) and ultraviolet ray (wavelength: 10 nm to 400
nm).
[0118] FIG. 7 is a view schematically illustrating an example of
attachment and its connection according to the present embodiment.
FIGS. 8 and 9 are each a view illustrating details of the
attachment and its tip end.
[0119] Referring to FIG. 7, the attachment 107a is held by the
probe drive unit 108, and connected via the optical fiber 126 to
the electromagnetic wave source and electromagnetic wave measuring
mechanism 124 and at the same time, connected via a transmission
line 113a to the electrical characteristic measuring unit 113. The
tip end 125b having the optical fiber 127 for electromagnetic wave
irradiation is connected to the attachment 107a; and the optical
fiber 127 is connected to the optical fiber 126 at the connection
section of the attachment 107a and the tip end 125b. The
transmission line 113a connected to the electrical characteristic
measuring unit 113 is isolated at a connecting section between the
attachment 107a and tip end 125b. When the attachment 107a and tip
end 125b are connected in this way, the electromagnetic wave
generated by the electromagnetic wave source and electromagnetic
wave measuring mechanism 124 can be transmitted via the optical
fiber 126 and irradiated via the optical fiber 127 on the
semiconductor sample 118.
[0120] The tip end 125b can be detached, as illustrated in FIG. 8,
from the attachment 107a; instead of the tip end 125b, an
attachment of another configuration, such as a tip end 125a or
125c, can be connected. When the tip end 125a is connected to the
attachment 107a, the probe 106 is connected to the transmission
line 113a at a connecting section between the tip end 125a and
attachment 107a, and the optical fiber 126 is isolated. In this
way, when the attachment 107a and tip end 125a are connected, the
electrical characteristic measuring unit 113 can measure, through
the probe 106, electrical characteristics of the semiconductor
sample 118. And when the tip end 125c is connected to the
attachment 107a, infrared ray emitted from a desired section of the
semiconductor sample 118 is received via an optical fiber 227 and
inputted via an optical fiber for transmission (not illustrated) to
the electromagnetic wave source and electromagnetic wave measuring
mechanism 124 to measure the intensity of infrared ray; when the
electromagnetic wave control mechanism 123 performs calculation
based on data of the intensity of infrared ray, the temperature of
the desired section of the semiconductor sample 118 can be
measured.
[0121] FIG. 10 is a lateral view of an optical microscope image
when an electrical characteristic measurement is performed on the
semiconductor sample according to the present embodiment. FIG. 11
is a view illustrating an SEM image when the electrical
characteristic measurement is performed.
[0122] Referring to FIGS. 10 and 11, the probes 106 are in contact
with the measurement pads 203, 204, 205 and 206 of the
semiconductor sample 118. Also, the optical fibers 127 and 227 are
arranged in the vicinity of a measurement section of the
semiconductor sample 118, the optical fibers facing the measurement
section. In this state, the electromagnetic wave source and
electromagnetic wave measuring mechanism 124 generates
electromagnetic wave (for example, infrared ray or ultraviolet
ray), and the electromagnetic wave is irradiated via the optical
fibers 126 and 127 on the measurement section of the semiconductor
sample 118. Also, infrared ray emitted from the measurement section
is inputted via the optical fiber 227 to the electromagnetic wave
source and electromagnetic wave measuring mechanism 124 to measure
the intensity of infrared ray. Data of the intensity of infrared is
sent to the electromagnetic wave control mechanism 123 and based on
the data, the temperature of the measurement section of the
semiconductor sample 118 can be measured. The control computer 114
regulates the intensity of infrared generated by the
electromagnetic wave source 121 so that the difference between a
setting temperature and the temperature of the measurement section
of the semiconductor sample 118 thus acquired is reduced, whereby
the temperature of the measurement section is regulated.
[0123] The other constituent components are identical to those of
the first embodiment of the present invention.
[0124] According to the present embodiment having the above
configuration, similarly to the first embodiment, since the
measurement section of the semiconductor sample 118 is locally
heated, the expansion and contraction of the sample drive apparatus
2 and sample measuring apparatus 3 can be suppressed and thus the
change of temperature can be made while the sample drift is
suppressed. Accordingly, when the change of temperature of the
semiconductor sample 118 is made, the measurement does not need to
be interrupted, as with the related art, until the sample drift
settles; thus the throughput can be improved significantly,
compared to the related art by which there is a wait until the
sample drift settles.
[0125] Further, the electromagnetic wave irradiation position can
be changed by driving the attachment 107a as with the probe 106, so
electromagnetic wave can be irradiated on a desired section.
[0126] In the embodiment of the present invention, the descriptions
were given by taking as an example, the case where the
electromagnetic wave source and the electromagnetic wave measuring
mechanism are integrated, but the present invention is not limited
thereto; the electromagnetic wave source and the electromagnetic
wave measuring mechanism may be separately arranged.
[0127] Also, the tip end having arranged therein the optical fiber
for electromagnetic wave irradiation and the tip end having
arranged therein the optical fiber used to receive electromagnetic
wave were separately provided, but the present invention is not
limited thereto; there may be used: a tip end having arranged
therein the two optical fibers; and an attachment via which the two
optical fibers of the tip end can be connected to the
electromagnetic wave source and electromagnetic wave measuring
mechanism, respectively. FIG. 12 illustrates an attachment 107b in
which an optical fiber 126a for electromagnetic wave irradiation
and an optical fiber 126b used to receive electromagnetic wave are
arranged. When this mechanism is used, it is possible to heat only
the probe 106, thus allowing prevention of the thermal loss and
thermal expansion occurring when the probe is brought into contact
with the sample.
[0128] Further, there may also be used a tip end of optical fiber
for electromagnetic wave irradiation having arranged therein a lens
unit.
[0129] In the first to third embodiments of the present invention,
there was described the case where an optical fiber is used as the
electromagnetic wave irradiation apparatus, but the present
invention is not limited thereto; for example, a lens or the like
arranged integrally or separately from the electromagnetic wave
generation apparatus may be used as the electromagnetic wave
irradiation apparatus.
* * * * *